This invention relates to management of volume migration between storage apparatuses.
The background of this application includes Patent Literature 1. The volumes belonging to storage devices A to D are virtually managed as a consolidation. A host recognizes the plurality of storage devices A to D as a single virtual storage device. The user can discretionally group the volumes of the storage system into storage layers 1 to 3. For example, the storage layer 1 may be defined as a highly reliable layer, the storage layer 2 as a low-cost layer, and the storage layer 3 as an archive layer. When the user designates volumes V1 and V2 to be migrated on a group basis together with the destination storage layer, data is relocated.    Patent Literature 1: U.S. Pat. No. 7,395,396